Added version 2.0 that I think looks better and also lets you set it closer to the pedal.
I just printed in PLA and they work perfectly for me, but any material should work. Just make sure you don't tighten too hard. If you find you're moving them back and tightening too much cracks them, either print in stronger material with higher infill or put thin rubber strips on the bottom.
The author marked this model as their own original creation.